Furnace



L. J. WEBER Dec. 18, 1951 FURNACE Filed May 1, 1946 ATTORNEYS:

INVENTOR LOUIS J. WEBER Patented Dec. 18, 1951 Phillips PetroleumCompany, a corporation of Delaware inventionrelates to fumaces. In oneof its morespecific aspectsit relates to an improved design of furnaceespecially adaptedfor heating petroleum or petroleum products and otherfluids. This application is ,a continuation-in-part of my copendingapplication; Serial No. 512,284, filed NovemberQ29, 1943 and now PatentNo. 2,528,564. L

Conventional furnaces, used for preheating or cracking petroleumproducts andfluids, ordinarily comprise a fire box set on a concretefoundation and having solid mas'onryyor refractory bridgewalls risingfrom the floor thereof to a point a spaced distance from. the top memberof the furnace. Such furnaces are ordinarily provided with a separateflue gas stack base or foundation and combustion gasesare' conveyed fromthe lowenportion of the furnace, between the bridgew'alls, through anunderground duct to the separate flue gas stack. Burners in suchconventional furnaces may be disposed in walls opposite the solidbridgewalls. Tubes may be provided as convection tubes between thebridge-' walls, and floor tubes, vertical sidewall tubes and roof tubesin a radiation section.

In furnaces of that type, the combustion gas and flames from the burnertend to'take a generally upwardlyand inwardly direction, the combustiongas escaping over .the topof the bridgewalls, down over the convectiontubes and out through a duct to the stack. That type of combustion gasflow fails to provide the amountof heat to thefloor tubes and verticalwall tubes that is provided to the roof tubes. Inasmuch as the flow ofmaterials to be heated or cracked is through the convection tubes. floortubes, vertical wall tubes, and rooftubes, the material passes from azone of relatively high heat input into zones of lower heatinput in thefloor and wall tubes. These low heat input zones are sometimes known ashigh temperature soaking, zones. Such zones are conducive to" theformation of tars often destructive. It is thus necessary, "in erectingthe conventional furnace, to first lay an extra heavy foundation inorder to withstand the destructive heat.

' The furnace of the instant invention solves the problems aboveenumerated. This device is an end fire box type furnace provided withslanting roof and floor sections connected by substantiallyVertical'side' walls; The slanting floor section is so supported on areinforced concrete foundation that it is air cooled and thus requiresless concrete than' 'is required inthe construction of a foundation orbase for conventional furnaces. I and are suspended from beams in theroof so as to be free floating within the furnaceand are spaced from thefurnace floor so as to allow the passage of combustion gas thereunder.'I'he'fiue stack is also supported by the beams in the roof whichsupport the bridgewalls. It will thus be' seen that the'stack of theinstant device may be somewhat shorter in length than that 'used inconventional furnaces. The above mentioned roof beams are preferablysupported by main central columns in line with the bridgewall outsidethe furnace structure. The main roof beams are parallel to the shortdimensions of the furnace and are supported at their ends by these maincentral columris. Tubes in the furnace of the instant invention are onlyin some ways similarly disposed to those within conventional furnaces.Convection coils are separated from radiation sections by hollowbridgewalls. Floor tubes are disposed along the slanting floor so thatthe tube bank slopes outwardly and upwardly,

parallel to the sloping floor. "Vertical wall tubes are aflixed in aposition, parallel to the vertical wall, and the roof tubes extenddownwardly and l outwardly parallel to the roof of the furnace. In

- the instant invention than in a conventional and carbon which reducesthe yield of desirable surfaces of the combustion cone emanating fromAnother disadvantage of the conventional furmice is that no provision ismade. for the escape of heat from the bridgewalls. For that reason it ismandatory thatthelrtemperature of the bridgewalls be kept under closesurveillance to keep from burning them out. The concrete founda-..

tion is'in much thelsame category. Highf'temperature, when applied touncooled concrete, is

this arrangement of tubes, more actual heat absorbing surface can beplaced in a furnace of furnace of equivalent fire box volume. I Thefloor and roof tubes are disposed in such a manner as to beapproximately parallel with the. sloping burners in the furnace wallsopposite the bridgewalls. With a furnace oi? the instant inventioncombustion gas ispartiallyVbottled up) in the radiant section above thelevel of the combustion gas outlet beneaththe b'ridgewallsy, Heattravels more equally toall parts of theradiationzonev and exposes theheat'absorption area. of fall of the floor tubes to amorel uniform heat;thanis, possible in conventional furnaces.

The bridgewalls are air cooled" Combustion The bridgewalls 6' are ingases flowing out of the radiant section into the convection sectionflow downwardly under the bridgewalls and contact that portion of thetubes below the combustion gas outlet and those in the convectionsection.

An object of my invention is to provide a simple and efficient furnaceunit which can be constructed on less ground space and with the use ofless critical materials than required by conventional designs.

Another object of my invention is to provide a furnace of such design asto utilize fully and efliciently the radiant heat to achieve a highlyeilicient rate of heat input to the tube coils.

I Many'other objects and advantages of my furnace will be apparent tothose skilled in the art from a careful study of the following detaileddescription, which taken in conjunction with the attached drawingrespectively describes and illustrates one embodiment of my invention.

In the drawing; Figure 1 is a cross sectional view of my furnace takenon the line [-1 of Figure 2.

Figure 2 is an end elevational view in diagrammatic form of a preferredembodiment of my furnace.

Figure 3 is a cross sectional view, in part, of the space between thetwo sides of the bridgewall taken on the line 3-3 of Figure 1.

Figure 4 is a sectional view of a furnace of this invention showing abridgewall and a furnace wall in spaced apart relation.

Referring to Figure l, the furnacetubes are separated into two maingroups. Some convection tubes are represented by l' and some radianttubes consisting of floor tubes are repre-' sented by I, slanting rooftubes by 2' and vertical side wall tubes by 3'. 'I'heconvection tubebank is suspended from a central framework comprising two principalcross beams 8' which in turn are supported by four central frameworkcolumns ll, vertically disposed and at the corners of an imaginaryrectangle. The cross beams 8' also support the stack 1'. Slanting roofbeams 16' are supported at one end by the beams 8 and at the other endby the buckstays or outer framework columns 13'. In turn, the slantingroof beams I6 support the fire box arch brick 9', and

the roof covering ID. The buckstays 13' support the refractory firebrick walls l1 and form end wall sections.

-The entire structure is supported upon any .suitable base such as areinforced concrete foundation, part of which is shown as IS. Therefractory linings for the furnace are attached to the beams by anysuitable and well known construction, and therooftubes 2' and thevertical wall tubes 3' aresupported by means of alloy castings Aattached'to beams li'and buckstays l3 respectively in any suitable andwell known manner.

Suspended also from the main beams 8' are the refractory bridgewalls 6which, as illustrated, are hollow and form vertical passages la (Figure3), and,are open at the ends so that air from the outside may enter themand flow inwardly and upwardly through these passages 8a and past theI-beams 8' and be discharged into the atmosphere. The burners 5' openinto the furnace in a direction to impinge their. flames onthebridgewalls 6'.

ed curtains-and comprise a series of vertical columns 8b connectedtogether at the bott'omby v means oi full floating I 9". The-refractorythe. form-of suspendwalls themselves are composed of fire brick tileattached to this curtain in any suitable and well in Figure 1. Thebridgewalls, being unattached at their ends to walls ii of the furnace,are truly suspended curtains capable of any necessary movement toallow,for expansion. and contraction thereof as shown in Fig. 4 of thedrawings.

The inner side member 2| of each of the bridgewalls extend up toward thestack at least sufliciently far as to protect the I-beams 8' from thehot combustion gases as they leave the conwalls and then upward throughsaid convection;

vection section and enter the base of the I stack 1f.

These bridgewalls 6' are in the form of suspended double walled curtainswith a ventilating space in each. Between the refractory walls 5' areseveral vertical steel I-beam type members 8b, see Figure 3. Theseseveral members are parallel to one another and the upper ends of whichare attached rigidly to the under side of the I- beam cross members 8',and thus hang downward from said I-beams. To these hanging steel members8b are attached lugs, or other hooking members, not shown, and uponwhich the refractory blocks forming the main refractory portion of thebridgewalls hang. To the bottom end of said vertically disposed I-beammembers 8b is attached a horizontally disposed I-beam or channel member19'. This member merely serves as a bottom framework member.

Thus from the bridgewall construction it will be seen that each entirebridgewall hangs from its respective upper I-beam 8' and may expand orcontract at will due to thermal causes.

The vertical I-beam members 8b and the horizontal I- or channel memberI! are perforated in the web to permit passage of atmospheric air forcooling. Thus atmospheric air enters the space within each bridgewall.and may pass from one opening 8a to another opening la and upon becomingheated rises to pass from these spaces around the I-beam 8' to theatmosphere. These hollow bridgewalls 8' extend all the way .across thefurnace and being spaced in the furnace as illustrated in Figure 1terminate above the floor of the furnace thereby leaving a i'rcepassageway from each fire box into the common convection tube section.Thus the burned gases may freely pass from the-combustion chambers orfire boxes downward and under the bridge tube section and finally intothe stack I proper. In operation, the fluid to be heated enters'thefurnace at the top of the convection tube bank I and progressesdownwardly to the floor tubes 4' then to the-lower wall tubes 3'. thenceto the roof tubes 2' and the top wall tubes 3 and finally to the outlet,which arrangement can be changed to suit the desired heatingcharacteristics. Burners I, iire directly against the radiant bridgewall6'.:-. Each combustion cone emanating from burners 5' moves ina'dire'ction such that its sides are substantially parallel with theslanting roof tubes 2' and slanting floor tubes l.

tubes 273, and 4' at an angle tending to provide even heat. distributionaround the tubes and between the different tubes. The flue gases passunder the suspended bridgewalls and up through the convection tube bankI to the stack I.

The concrete floor slab ll' sloping upwardly and outwardly from acentral foundation portion to the end walls I1 is prevented frombecoming overheated by being air cooled on the bottom side. The radiantbridgewalls 6' are cooled by air which enters at the bridgewall endspassing into the spaces within the walls and thence upwardly passingthrough the spaces 8a within the walls and exits from the walls aroundthe I- beams 8' to the' atmosphere.

The large modern furnaces usually have a separate base or foundation forthe flue gas stack and often the hot gases are conveyed some distanceunderground to the stack. It may be necessary to locate the stack atsuiiicient distance to provide a working area around the furnace proper.While such stacks must of necessity begin, at ground level, the stack inthis novel design rests upon and is supported by the furnace structure.Further advantages of this design are: (1) Less space required. (2)Lower draft loss because of duct elimination. (3) Less stack because oflower draft loss and because of the elimination of the stack sectionbetween furnace roof and ground. forcing steel required because of ductelimination. (5) Lower refractory maintenance because of ductelimination. (6) More heat absorbing surface can be placed in a furnaceof the equivalent fire box volume. (7) The surface may be placed so thatall tubes receive maximum benefit of the radiant heating surface. (8) Nooverhead or underground .flue gas ducts are required. (9) The furnacefloor is air cooled reducing concrete foundation requirements. (10) Thefurnace structure may be used to support the flue gas stack. (11) Floortubes are supported by beams of refractory material eliminating the useof alloy castings. 12) The bridgewall is air cooled and is free to movepermitting higher operating temperatures and requiring less refractorymaterial.

In this design, the floor coil is tilted toward the radiant bridgewallin order to secure optimum heat distribution on the tubes. Floor androof tubes are each disposed in such a manner as to be approximatelyparallel with the sloping surfaces of the combustion cone emanating fromthe burner. Tubes disposed in a horizontal Plane which are not parallelto the combustion cone do not have this advantage. By disposing thetubes parallel to the combustion cone in this design, the allowable heatrelease per cubic foot of furnace volume is more than double that of theconventional furnace. The tubes in this design absorb heat from the firebox, with approximately the same efiiciency because the relationshipbetween the tube heat absorbing surfaces and each cubic unit of the firebox volume is approximately constant throughout the radiant section.

It will be obvious to those skilled in the art that many variations andmodifications in the constructional details may be made and yet remainwithin the intended spirit and scope of my invention. Materials ofconstruction may be selected from among those commercially available andsuitable for the purpose at hand.

One modification of my furnace includes a single unit installation incontrast tothe double (4) Less concrete and reinunit as hereinbeforedescribed. A single unit may be composed of one fire box with itsbumers5 as in Figure'l, roof tubes in a plane sloping upward and away, andfloor tubes in a plane sloping downward and away from the burners 5',and wall tubes above and below the burners 6'. One double hollowbridgewall receive heat from the single fire box, while the convectiontubes will be between the double hollow bridgewall and a back wall.-Thus the drawing of Figure 1 may be modified to illustrate thisembodiment by merely removing the right hand fire box and replacin itshollow bridgewall by a single, simple refractory wall which extends fromthe base of the stack 1' to the floor of the furnace. The four maincolumns l4 and the two upper main I-beams 8' may be unchanged. These twoI-beams may support the stack 1' as in Figure 1. In this single unitfurnace there will be one fire box, and one suspended hanging bridgewalland a more nearly rigid refractory back wall. The convection tubes aresituated in the volume between the one hanging bridgewall and therefractory back wall through which volume combustion gases from thesingle fire box passing under the lone hanging bridgewall pass upward tothe base of the stack.

In either embodiment of my invention, wherein a self ventilatingbridgewall is used, the ventilation through each of the spaces 8a. maybe controlled or regulated by adjustment of bafiles I 8. These bafflesmerely slide horizontally to open fully, or to open partly the spaces oneither side of the I-beam 8 to control the amount of cooling airescaping from each space 8a.

Having described my invention, I claim:

1. A tube heater comprising a central framework extending from a centralground base to the .top of said heater; a floor extending upwardly saidbridgewalls being suspended solely from said cross beams, beingunattached at their ends and spaced from said'floor sufficiently toallow gas passage therebetween and dividing said heater into tworadiation sections and enclosing a conheater, whereby two walls areformed on opposite side of said vertical supportmembers, refractorysections fastened to said horizontal support member and connecting thetwo walls formed on said vertical support members whereby a continuouspassageisformed through said vertical support and along the length ofeach bridgewall between said connected'oppos'itely disposed walls;baflie 'members slidably aflixed in the open upper end 1 of each saidbridgewall, whereby the opening at the upper endof said bridgewalls canbe controlled in size; a stack extending upwardly from and supported bysaid central framework and communicating with said radiation sectionsthrough said convection section and said spaces beneath saidbridgewalls, said bridgewalls being expandible laterally and vertically;banks of heating tubes disposed within said radiation sections so as tobe substantially parallel respectively to said roof assemblies and saidsloping floor; a bank of heating tubes within said convection section;and burners mounted in said radiation sections and directed toward saidbridgewalls.

2. A tube heater comprising a central framework extending from a groundbase to the top of said heater; a floor extending upwardly and outwardlyfrom said ground base to at least one side of said heater; a first wallextending upwardly from an outer end of said outwardly and upwardlyextending floor; at least one cross beam laterally extending across saidheater, spaced from the ends of said heater and attached to the upperportion of said central framework;

a roof assembly extending downwardly and outwardly from said cross beamto said first wall; side walls closing the otherwise unclosed sides ofsaid heater; a bridgewall extending downwardly into said heater fromeach said cross beam, said bridgewall being suspended solely from saidcross beam, extending the width of said heater, beingunattached at itsends and spaced from said floor sufficiently to allow gas passagetherebetween and dividing a radiation section from a convection section,each said bridgewall being open at its upper end and comprising aplurality of perforate vertical support members rigidly affixed at theirupper ends to one of said cross beams, a horizontal support memberattached to the lower ends of said vertical support members, refractorysections fastened to opposite sides of said vertical support members andextending across said heater, whereby two walls are formed on oppositesides of said Vertical support members, refractory sections fastened tosaid horizontal support member and connecting the two walls formed onsaid vertical support members whereby a continuous passage is formedthrough said vertical supports and along the length of each saidbridgewall between said connected opposite ly disposed walls; bafllemembers slidably ailixed in the open upper end of each said bridgewall,whereby the opening at the upper end of said bridgewalls can becontrolled in size; a stack supported by said framework andcommunicating with said radiation section through said convectionsection and said space beneath said bridgewalls, each said bridgewallbeing expandible laterally and vertically; banks of heating tubesdisposed within each said radiation section so as to be substantiallyparallel. respectively to each said roof assemblies and said slopingfloor; a bank of heating tubes within said convection section; andburners mounted in said radiation section and directed toward each saidbridgewalls.

LOUIS J. WEBER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,591,431 Nash et a1. July 6,1926 1,901,970 Huff Mar. 21, 1933 2,029,293 Alther Feb. 4,1936 2,105,819Parsons Jan. 18, 1938 2,105,821 Parsons Jan. 18, 1938 2,111,380 BarnesMar. 15, 1938 2,129,900 Barnes Sept. 13, 1938 2,132,517 Reintges Oct.11, 1938 2,134,000 Mayo Oct. 25, 1938 2,142,956 Schauble Jan. 3, 19392,149,831 Bergman Mar. 7, 1939 2,205,776 Hosbein June 25, 1940 2,229,253Nash et a1. Jan. 21, 1941 2,326,473 Lyster Aug. 10, 1943 2,335,317Sherman Nov. 30, 1943 2,528,564 Weber Nov. 7, 1950

